RxJS：结束三个承诺，区分结果

问题描述

我有三个promise，Rest请求返回数据列表。

第三个有前两个列表的引用（ids），所以我想把这些id映射到相应的名字数据。

映射不是问题，我只是使用Lodash。

但问题是在开始计算这个映射之前等待三个promises解决。

I have three promises, Rest requests returning lists of data.
The third one has references (ids) to the first two lists, so I want to map these ids to corresponding names when I have all the data.
The mapping isn't an issue, I just use Lodash for that.
But the issue is to wait for the three promises to resolve before starting to computing this mapping.

我想出去使用 concat（）：

Rx.Observable.concat(p1, p2, p3).subscribe(
function onNext(list)
{
  // Assign the list to the corresponding variable in the scope
},
function onError(e)
{
  // Notify of error
},
function onCompleted()
{
  // Do the mapping
}
);

我的问题是 onNext（）将以随机顺序调用。 IE浏览器。我不知道我在某个时候收到了哪个列表，并且很难从它包含的数据中得知。

My problem is that onNext() will be called in random order. Ie. I don't know which list I receive at some point, and it is hard to tell from the data it contains.

有没有办法跟踪产生哪些承诺清单？拉链？ concatMap？ concatMapObserver？我承认我还没有完全理解最后两个的使用...

Is there a way to track which promises produced which list? A kind of zip? concatMap? concatMapObserver? I admit I haven't fully understood the usage of the last two...

推荐答案

如果这些是我们正在谈论的承诺，我想你可以看一下 forkJoin 运算符。参看，

If these are promises we are talking about, I think you can have a look at the forkJoin operator. Cf. https://github.com/Reactive-Extensions/RxJS/blob/master/doc/api/core/operators/forkjoin.md, http://xgrommx.github.io/rx-book/content/observable/observable_methods/forkjoin.html

你可以得到类似的东西：

You could then have something like :

Rx.Observable.forkJoin(p1, p2, p3, function(p1,p2,p3){
/* your combining code here */
})

简而言之， forkJoin 具有类似于 RSVP.all 的语义，如果您知道promises库RSVP。

In short, forkJoin has semantics similar to that of RSVP.all if you know the promises library RSVP.

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